The contribution of the Isaac Master (the young Giotto according to some scholars) to the clerestory frescoes of the upper church was not limited to the two scenes with Isaac from which the painter's name derives. He and his workshop were evidently assigned the decoration of the clerestory and vault zone in the first bay and on the entrance wall. Regrettably, most of the paintings attributed to the Isaac Master and his workshop have been destroyed. The only work that substantially survives is the vault with the church fathers, which until 1997 was fully intact, but it was damaged heavily by the earthquake of September 1997 that caused the east vault cell to collapse.